Gas charge driven switching devices for medium voltage use are well known.
An example of such a switchgear is disclosed in the DE 26 54 441 A1. The actuator of the switchgear is actuated by a gas charge capsule. Several capsules are deposited in a magazine. In this known solution, the chemical charge is not located directly on the contact rod.
Thus, if several mechanical means are implemented between the load transmission and the contact rods, mechanical play is introduced into the actuation movement.
Because of this, the gas charge has to be positioned as near as possible to the contact or the contact rod, which has to be actuated.
However, the chemical charge is located near the contacts or the contact actuators and especially in case of arrangement in series, those parts are under high voltage potential. To ignite this chemical charge, a signal cable has to be used. As a result, the electrical contact to the chemical charge is on high voltage potential. The other side of the cable has to be managed electrically in such a way that the ignition system or the cable, or whatever component is used, should isolate between the different voltage potentials and/or the ground potential, in order to produce high security for the operation of this switch gear. Thus, there is a need to have an insulated part which is carrying the electrical power from one or earth potential or ground potential to low, medium or high voltage potential. A known technique of handling this problem is to install a transformer between earth potential and higher voltage level. By installing a special transformator, it is possible to produce a galvanic barrier for insolating these two electric levels.